/****************************************************************************
 *
 * Copyright 2019 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/****************************************************************************
 * os/binfmt/libelf/libelf_ctors.c
 *
 *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <string.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>

#include <tinyara/kmalloc.h>
#include <tinyara/binfmt/elf.h>

#include "libelf.h"

#ifdef CONFIG_BINFMT_CONSTRUCTORS

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Types
 ****************************************************************************/

/****************************************************************************
 * Private Constant Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: elf_loadctors
 *
 * Description:
 *  Load pointers to static constructors into an in-memory array.
 *
 * Input Parameters:
 *   loadinfo - Load state information
 *
 * Returned Value:
 *   0 (OK) is returned on success and a negated errno is returned on
 *   failure.
 *
 ****************************************************************************/

int elf_loadctors(FAR struct elf_loadinfo_s *loadinfo)
{
	FAR Elf32_Shdr *shdr;
	size_t ctorsize;
	int ctoridx;
	int ret;
	int i;

	DEBUGASSERT(loadinfo->ctors == NULL);

	/* Allocate an I/O buffer if necessary.  This buffer is used by
	 * elf_sectname() to accumulate the variable length symbol name.
	 */

	ret = elf_allocbuffer(loadinfo);
	if (ret < 0) {
		berr("elf_allocbuffer failed: %d\n", ret);
		return -ENOMEM;
	}

	/* Find the index to the section named ".ctors."  NOTE:  On old ABI system,
	 * .ctors is the name of the section containing the list of constructors;
	 * On newer systems, the similar section is called .init_array.  It is
	 * expected that the linker script will force the section name to be ".ctors"
	 * in either case.
	 */

	ctoridx = elf_findsection(loadinfo, ".ctors");
	if (ctoridx < 0) {
		/* This may not be a failure.  -ENOENT indicates that the file has no
		 * static constructor section.
		 */

		binfo("elf_findsection .ctors section failed: %d\n", ctoridx);
		return ret == -ENOENT ? OK : ret;
	}

	/* Now we can get a pointer to the .ctor section in the section header
	 * table.
	 */

	shdr = &loadinfo->shdr[ctoridx];

	/* Get the size of the .ctor section and the number of constructors that
	 * will need to be called.
	 */

	ctorsize = shdr->sh_size;
	loadinfo->nctors = ctorsize / sizeof(binfmt_ctor_t);

	binfo("ctoridx=%d ctorsize=%d sizeof(binfmt_ctor_t)=%d nctors=%d\n", ctoridx, ctorsize, sizeof(binfmt_ctor_t), loadinfo->nctors);

	/* Check if there are any constructors.  It is not an error if there
	 * are none.
	 */

	if (loadinfo->nctors > 0) {
		/* Check an assumption that we made above */

		DEBUGASSERT(shdr->sh_size == loadinfo->nctors * sizeof(binfmt_ctor_t));

		/* In the old ABI, the .ctors section is not allocated.  In that case,
		 * we need to allocate memory to hold the .ctors and then copy the
		 * from the file into the allocated memory.
		 *
		 * SHF_ALLOC indicates that the section requires memory during
		 * execution.
		 */

		if ((shdr->sh_flags & SHF_ALLOC) == 0) {
			/* Allocate memory to hold a copy of the .ctor section */

			loadinfo->ctors = (binfmt_ctor_t *)kmm_malloc(ctorsize);
			if (!loadinfo->ctors) {
				berr("Failed to allocate memory for .ctors\n");
				return -ENOMEM;
			}

			/* Read the section header table into memory */

			ret = elf_read(loadinfo, (FAR uint8_t *)loadinfo->ctors, ctorsize, shdr->sh_offset);
			if (ret < 0) {
				berr("Failed to allocate .ctors: %d\n", ret);
				return ret;
			}

			/* Fix up all of the .ctor addresses.  Since the addresses
			 * do not lie in allocated memory, there will be no relocation
			 * section for them.
			 */

			for (i = 0; i < loadinfo->nctors; i++) {
				FAR uintptr_t *ptr = (uintptr_t *)((FAR void *)(&loadinfo->ctors)[i]);

				binfo("ctor %d: %08lx + %08lx = %08lx\n", i, *ptr, (unsigned long)loadinfo->binp->sections[BIN_TEXT], (unsigned long)(*ptr + loadinfo->binp->sections[BIN_TEXT]));

				*ptr += loadinfo->binp->sections[BIN_TEXT];
			}
		} else {

			/* Save the address of the .ctors (actually, .init_array) where it was
			 * loaded into memory.  Since the .ctors lie in allocated memory, they
			 * will be relocated via the normal mechanism.
			 */

			loadinfo->ctors = (binfmt_ctor_t *)shdr->sh_addr;
		}
	}

	return OK;
}

#endif							/* CONFIG_BINFMT_CONSTRUCTORS */
